基于随机变量的大坝自振频率计算
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摘要
针对地震对水工结构的作用输入及结构的地震响应机理的复杂性,基于随机动力学分析理论,采用结构动力学基本方程,构建了考虑动力水作用、地震时地面加速度及结构自身弹性模量等随机变量的结构自振频率数学模型,并应用于某双曲高拱坝中。数值计算结果表明,不同振型对应的结构自振频率均值有一定的变化规律,而变异系数变化不大,但两者具有一定的相关性,均受随机输入变量的影响,且表现出相同的随机性。为进一步研究强地震荷载下高库大坝结构的破坏机理提供了参考。
On account of complex mechanism of input earthquakes and structure response,and based on the theory of stochastic dynamics analysis,the basic dynamics equations of structure is applied to establish the mathematical model of natural frequency of the structure by considering the random variables,such as dynamic water pressure,earthquake ground acceleration and elastic modulus of the structure.And then the model is applied to a certain double-curvature high arch dam.Numerical results show that the average value of natural vibration frequency in different vibration type has a certain change rule,but the coefficient of variation changes small and the two natural frequency of average value and coefficient of variation have a certain correlation;the common characteristics of randomness is affected by random input variable.Therefore,it provides reference for studying dam failure mechanism under seismic load.
On account of complex mechanism of input earthquakes and structure response,and based on the theory of stochastic dynamics analysis,the basic dynamics equations of structure is applied to establish the mathematical model of natural frequency of the structure by considering the random variables,such as dynamic water pressure,earthquake ground acceleration and elastic modulus of the structure.And then the model is applied to a certain double-curvature high arch dam.Numerical results show that the average value of natural vibration frequency in different vibration type has a certain change rule,but the coefficient of variation changes small and the two natural frequency of average value and coefficient of variation have a certain correlation;the common characteristics of randomness is affected by random input variable.Therefore,it provides reference for studying dam failure mechanism under seismic load.
引文
[1]于海英,公茂盛,金波,等.水库地震的地震动特性[J].自然灾害学报,2006,15(5):188-193.
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[3]Alves S W,Hall J F.Generation of Spatially Nonu-niform Ground Motion for Nonlinear Analysis of aConcrete Arch Dam[J].Earthquake Engineering andStructural Dynamics,2006,35(11):1 339-1 357.
[4]Amador T G,James O J.Energy Demands for Seis-mic Design Against Low Cycle Fatigue[J].Earth-quake Engineering and Structural Dynamics,2007,36(3):383-404.
[5]中国水利水电科学研究院,电力工业部昆明勘测设计研究院,电力工业部西北勘测设计研究院,等.水工建筑物抗震设计规范(DL5073-1997)[S].北京:中国电力出版社,1997.
[6]Clough R W,Rapheal J M,Mojtahedis S.ADAP AComputer Program for Static and Dynamic Analysisof Arch Dams[A].Report of PEERC[C].U CBerkeley,1973.
[2]陈厚群.当前我国水工抗震中的主要问题和发展动态[J].振动工程学报,1997,10(3):253-257.
[3]Alves S W,Hall J F.Generation of Spatially Nonu-niform Ground Motion for Nonlinear Analysis of aConcrete Arch Dam[J].Earthquake Engineering andStructural Dynamics,2006,35(11):1 339-1 357.
[4]Amador T G,James O J.Energy Demands for Seis-mic Design Against Low Cycle Fatigue[J].Earth-quake Engineering and Structural Dynamics,2007,36(3):383-404.
[5]中国水利水电科学研究院,电力工业部昆明勘测设计研究院,电力工业部西北勘测设计研究院,等.水工建筑物抗震设计规范(DL5073-1997)[S].北京:中国电力出版社,1997.
[6]Clough R W,Rapheal J M,Mojtahedis S.ADAP AComputer Program for Static and Dynamic Analysisof Arch Dams[A].Report of PEERC[C].U CBerkeley,1973.
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